Edge Termination Doping Layout for High-Breakdown Semiconductors
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Solution Overview
Problem
Conventional semiconductor devices face challenges in achieving both high breakdown voltage and reduced device area due to electric field concentration at the corner portions of the edge termination structure, leading to processing difficulties and decreased breakdown voltage.
Innovation Solution
The semiconductor device incorporates a low-concentration semiconductor layer of a first conductivity type and a second semiconductor layer with a lower impurity concentration, arranged in the edge termination structure region, mitigating electric field concentration and enabling improved breakdown voltage without a mesa portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a conventional edge termination structure is used, then the device area can be reduced, but the breakdown voltage decreases due to electric field concentration at corner portions
Solution Approach 1:
The patent applies local quality by creating a guard ring structure with specific doping characteristics only in the edge termination region, while maintaining different doping characteristics in the active region. The guard ring has a doping concentration and type designed specifically for edge termination, creating localized electrical properties that mitigate electric field concentration at corners without affecting the active region performance.
Solution Approach 2:
The guard ring acts as an intermediary structure between the active region and the edge termination region. It mediates the electric field distribution by providing a transition zone with controlled doping characteristics, preventing direct electric field concentration at the sharp corners of the active region while maintaining proper device operation.
2Area of stationary object
If the edge termination structure region has a shorter horizontal width, then the device area is reduced, but processing difficulties increase and breakdown voltage decreases
Solution Approach 1:
The guard ring structure is formed preliminarily during the manufacturing process, establishing the edge termination characteristics before final device completion. This preliminary structuring of the edge region with appropriate doping allows for optimized horizontal width without compromising processing ease, as the doping profile is established in advance to prevent electric field concentration.
3Reliability
If a mesa portion is used for edge termination, then the breakdown voltage can be maintained, but the device area increases and processing becomes more difficult
Solution Approach 1:
The patent changes the doping parameters (concentration and type) in the edge termination region to achieve breakdown voltage maintenance without requiring a mesa structure. By adjusting the doping concentration and type in the guard ring and edge termination region, the electric field distribution is optimized to prevent concentration at corners, allowing a planar structure with reduced area.
Data Source
AI summary
A semiconductor device has an active region through which current flows and an edge termination structure region arranged outside the active region. The semiconductor device includes a low-concentration semiconductor layer of a first conductivity type, and formed in the edge termination structure region, on a front surface of a semiconductor substrate. The semiconductor device includes a second semiconductor layer of a second conductivity type, in contact with one of a semiconductor layer of the second conductivity type in the active region and a semiconductor layer of the second conductivity type in contact with a source electrode. The second semiconductor layer has an impurity concentration that is lower than that of the semiconductor layer, and the second semiconductor layer is not in contact with a surface of the semiconductor substrate.